Hole-initiated melting process of thin films.

Abstract

We perform numerical and experimental studies on the melting process of thin films initiated by a small hole in the continuum regime. The presence of a nontrivial capillary surface, namely the liquid/air interface, leads to a few counterintuitive results: (1) The melting point is elevated if the film surface is partially wettable, even with a small contact angle. (2) For a film that is finite in size, melting may prefer to start from the outer boundary rather than a hole inside. (3) More complex melting scenarios may arise, including morphology transitions and the "de facto" melting point being a range instead of a single value. These are verified by experiments on melting alkane films between silica and air. This work continues a series of investigations on the capillary aspects of melting. Both our model and analysis approach can be easily generalized to other systems.